Electrical submersible pumps (ESP) are used in the geothermal, oil and gas and water wells for producing fluids from the subterranean well. Traditionally, subterranean wells are completed in porous formations having naturally high permeability and which contain water, oil, natural gas, heated water, brine and/or steam in relative close proximity to the surface of the earth. Geothermal wells are also completed in low permeability formations that contain little to no geothermal fluid. For these low permeability formations, the permeability of the formation is engineered or enhanced through stimulation methods such as pumping of cold water to generate fractures within the formation. This creates or enhances a geothermal reservoir in the high temperature formation to enable development of an Engineered or Enhanced Geothermal System (EGS). Currently, ESP systems are not suitable for most high temperature applications, especially geothermal applications. ESP systems are susceptible to pump cavitation due to boiling in high temperature wells producing water and/or brine above 100° C. Electrical motors in ESP systems are tested at temperatures of up to 2200° C. at low flow rates while high volume ESPs are designed to withstand temperatures up to 200° C. The temperature of the earth grows hotter with increasing depth, and geothermal systems can have well temperatures ranging from 150° C. to greater than 300° C. Advanced methods for recovering heavy oil may involve the use of steam to mobilize or heat oil and water produced from the reservoir having a temperature above 200° C. ESP systems used to recover oil with hot water in these steam flood wells are exposed to temperatures above design limits of current ESPs.
Line shaft pumps have been used in the petroleum, mine dewatering and geothermal industry for high temperature applications. Line shaft pump arrangements include a pump positioned in the subterranean well at depth calculated to allow for draw down, gas breakout, boiling of the fluid in the well and frictional pressure drop in the well. The pump is driven by a pump motor positioned at the surface which turns the shaft connected to the pump in the well. Line shaft pumps cannot be set at deep depths, because the long line shaft flexes too much causing vibration, stress on the bearings and excessive wear in the pump bowls. Currently, due to these problems, line shaft pumps cannot be set at depths greater than about 2000 ft. Subterranean wells including high temperature and EGS wells require pumps; to be set at depths greater than 2,000 feet. Therefore, line shaft, pumps are not suitable for many high temperature and deep well applications.
The present application is directed to systems and methods for cooling electrical submersible pumps and components thereof.